Milling apparatus



July 24, 1962 A. DI MINO MILLING APPARATUS Filed Deo. 21, 1960 FLUDCONTROL :'PUMP UPPLY" MEANS 58 -r T T* INVENTOR. A LFoNso DlMlNo @iQ/MATTORNEY United States Patent Oce 3,345,933 Patented July 24, 19623,045,933 MHJLING APPARATUS Alfonso Di Mino, Woodcliff Lake, NJ.,assignor to Burroughs Corporation, Detroit, Mich., a corporation ofMichigan Filed Dec. 21, 1960, Ser. No. 77,397 7 Claims. (Cl. 241--111)This invention relates to milling apparatus for use in pulverizingmaterials such as oils, paints, pigments and all types of mineral,vegetable, and animal substances.

Milling apparatus of the type contemplated by the present inventionincludes those types of mills known as ball mills, roll mills, andcolloidal mills. Each of these types of mills has is own particularcharacteristics and utility. However, there is no commercially availablemilling apparatus which includes, in one structure, means for performingthe functions of two or all of these types of mills. Such apparatus ismade available by the present invention in a comparatively simple andinexpensive structure which has all of the advantages of these separatetypes of mills.

The principles `and objects of the invention are directed toward theprovision of improved milling apparatus which combines in a singlestructure means for performing several dilferent types of millingoperations.

Briefly, milling apparatus embodying the invention includes a housing inwhich a central roll is loosely and rotatably mounted. Adjacent to andsurrounding this central roll `are a plurality of driven rollspositioned in operative relation with the central roll. The spacebetween the driven rolls and the wall of the housing is sullicientlysmall to achieve milling action between these rolls and the wall of thehousing. A plurality of hollow tubes are rigidly supported within thehousing and thus lend strength and rigidity thereto. Since the tubes arehollow, they are also readily adapted for use in circulating a coolingor heating fluid through the housing whereby the temperature of materialbeing milled may be controlled.

The mill provides roll mill action between each driven roll and thecentral roll, and both ball mill and colloidal mill action in the spacebetween the driven rolls and the wall of the housing.

The invention is described in greater detail by reference to the drawingwherein:

FIG. 1 is an elevational view, partly in section, of the apparatus ofthe invention;

FIG. 2 is a view looking into one end of the apparatus, and

FIG. 3 is asectional view along the line 3-3 in FIG. l.

Referring to the drawing, milling apparatus embodying the inventionincludes a `hollow cylindrical housing 12 comprising a side wall 13 andend walls 14 and 16 in fluid-tight engagement therewith. The end wallsare adapted to be removed from `the side wall, if desired. The side wall13 is` provided with a filling aperture 18 having a cap 2l) throughwhich the housing is lilled, and a suitable gas pressure relief valve22. A material discharge port 24 is provided in one of the end walls 14or 16.

The mill 10 includes a first central cylindrical roll 26 positioned onthe axis of the housing. The central roll is made of steel or the likeand may have a smooth, grooved, or rough external surface as required.The central roll is loosely mounted on a shaft 28 which is oriented onthe horizontal axis of the housing 12 `and which is rotatably mounted insuitable bearing surfaces in the end walls 14 and 16. The shaft 28extends a suitable distance beyond one of the end walls, for example endwall 14, and carries a gear 29 and a pulley 30. r[The pulley 30 iscoupled to a Suitable power source such as a motor 31.

A plurality of peripheral rolls 32, 34, 36 are mounted within thehousing surrounding and in operative relation with the central roll 26.The peripheral rolls are spaced equidistantly from each other about thecentral roll. The peripheral rolls are made of steel or some othersuitable material, and have smooth, grooved, or rough external surfaces.The peripheral rolls 32, 34, and 36 are secured to `and rotated byshafts 37, 33, and 39, respectively, which are suitably rotatablyjournalled in the end walls 14 and 16. Shafts 37, 38, and 39 extendthrough the wall 14 and terminate outside the housing where they carrygears 4t), 42, and 44, each of which meshes with gear 29 on shaft 28.

According to one aspect of the invention, a minimum spacing 45 isprovided between the side wall 13 of the housing and the adjacentperipheral rolls 32, 34, and 36. With such a mechanical arrangement andwith relatively high speed rotation of the peripheral rolls, millingaction is achieved in the space between these rolls and the wall of thehousing due to turbulence and friction. Thus, the spacing 45 is designedto provide optimum milling action with the selected roll speed ofrotation. This spacing is as small as possible and, preferably, only afraction of an inch. A spacing in the range of about 1/15 to J/32 of aninch is satisfactory.

The mill 1t) includes a plurality of rigid spacer members 46, 43, andSti secured within the housing 12 between the end walls 14 `and 16. Thespacers are preferably made of steel or some similar material and arehollow so that a lluid may be circulated through them for regulating thetemperature of the material inside the housing. The spacers are eachprovided with a pair of hollow threaded end pipes 46', 43 and 50',respectively, which extend through the walls 14 and 16 `of the housing.Outside the housing, nuts 52 or other suitable fasteners are secured tothe threaded pipes to hold the spacers securely in position. Inaddition, a iirst hollow annular fluid-circulating pipe 54 is secured bysuitable iluidtight littings *55 to one set of end pipes adjacent to theend wall 14, and a similar fluid-circulating pipe 56 is `secured byfittings 57 to the other set of end pipes adjacent to the other end wall16. The pipes are suitably coupled to a iluid supply 58 and pumpingmeans 60 for circulating the lluid through the spacers 46, 48, `and 50.Suitable means 61 are also included in the fluid supply system forregulating the temperature of the circulating duid.

In `operation of the invention, the housing 12 is lled with raw materialto be milled, the material being admitted through the opening 18 in thewall 13. Power is applied through the pulley Sti and the gears 29, 40,42, and 44, and the peripheral rolls 32, 34 and 36 are rotated thereby.As these rolls rotate, the material contained within the housing passesbetween them and the central, loosely held roll 26 and the central rollis caused to rotate due to the frictional forces developed. As the partscontinue to rotate with respect to each other and the material passesbetween the peripheral rolls and the central roll, the desired millingoperation is achieved. This action of the apparatus of the inventioncomprises, in effect, roll mill action. In addition, as the peripheralrollers rotate, material which lies between the rollers and the sidewall is milled by ball mill action as the particles abrade each other.The ball milling effect may be enhanced by intermittently reversing thedirection of rotation of the mill rolls. A third effect, colloidalmilling, is achieved as the material being milled is driven against theinner `surface of the side wall of the housing due to turbulencedeveloped by the rotating rolls. The milling operation is aided by thetemperature control efected by the tluid which may be circulated throughspacers 46, 48, and Sil.

What is claimed is:

1. Milling apparatus including a housing, a central roll in said housingand freely rotatable on a shaft, and a plurality of rolls surroundingand in operati-ve relation with `said central roll, each of saidplurality of rolls being adapted to be positively driven, the spacebetween said driven rolls and the wall of said housing being small sothat, as said positively driven rolls rotate, considerable turbulence isdeveloped in said space and the milling action is aided by saidturbulence.

2. Milling apparatus including a housing, a central roll in said housingand freely rotatable on a shaft, a plurality of rolls surrounding and inoperative relation with said central roll, each of said plurality ofrolls being adapted to be positively driven, the space between saiddriven rolls and the wall of said housing being of the order of afraction of an inch so that, yas said positively driven rolls rotate,considerable turbulence is developed in said space and the millingaction is aided by said turbulence, and means within said housing forcirculating a temperaturecontrolling uid therethrough.

3. Milling apparatus including a housing, a central roll in said housingand freely rotatable on a shaft, a plurality of rolls surrounding and inoperative relation with said central roll, each of said plurality ofrolls being adapted to be positively driven, the space between saiddriven rolls 4and `the wall of said housing being small so that, as saidpositively driven rolls rotate, considerable turbulence is developed insaid space and the milling action is aided by said turbulence, and aplurality of hollow spacers within said housing and having means forcirculating a temperature-controlling iiuid therethrough.

4. Milling apparatus including a housing, a central roll in said housingand freely rotatable on a shaft, and a plurality of roll-s surroundingand in operative relation With said central roll, each of said pluralityof rolls being adapted to be positively driven, said driven rolls beingadapted to drive said centrai roll through the material being milled `asit passes between them, the space between said driven rolls and the wallof `said housing being small so that, as said positively driven rollsrotate, considerable turbulence is developed in said space and themilling action is aided by said turbulence.

5. The mill dened in claim 4 and including means within said housing forcirculating a temperature-regulating fluid therethrough.

6. The mill defined in claim 4 and including a plurality of hollowcylinders iiXed in position inside said housing and adapted to have atemperature-regulating fluid circulated therethrough whereby thetemperature of the material being milled is regulated.

7. The milling apparatus defined in claim 4 wherein said housingincludes two end walls, and a plurality of hollow cylinders are xed inposition between said end walls, said cylinders being adapted to have vatemperatureregulating lfluid circulated therethrough whereby thetemperature of the material being milled is regulated.

References Cited in the tile of this patent UNITED STATES PATENTS

